Conventionally, as a solar radiation shielding film, a heat ray cutting film is known. As an example of the heat ray cutting film, PTL1 discloses a transparent laminate film of a multilayer film type in which metal oxide layers and metal layers are alternately laminated on one side of a transparent polymer film.
Further, in PTL2, a technology is disclosed in which, in a heat ray reflecting glass formed by laminating a film having a high heat ray reflectance on a glass substrate, the film has a surface resistance of 500Ω/□ or less, a dividing groove is formed on the film, and a solar radiation transmittance of the film is 50% or less. In PTL2, it is described that, although the film allows radio waves to pass with the groove having a width of about 50 μm, the heat insulating film becomes an electrically continuous body when the groove width is too small, because an electrical current jumps over a gap of the groove by a displacement current.
Further, PTL3 discloses a laminate structure that is obtained by placing between two transparent substrates a thermoplastic resin film having a conductive film on a rough surface thereof and then by bonding the substrates and the film to each other.